1. Field of the Invention
The present invention relates to an image reading device. More particularly, the present invention relates to an image reading device capable of precisely reading an image by correction of inappropriate portions.
2. Description Related to the Prior Art
There is an image reading device, which includes an image sensor such as CCD, and reads a frame image from developed photo film or an original of other types. In the image reading device, a light source having a lamp applies light to the original, from which the reflected light is read by the image sensor to obtain digital image data. The image data is subjected to enlargement, compression, compensation and other treatment of image processing. After this, the image frame is printed to photographic paper or other recording medium according to the image data being processed.
The image reading device reads the frame image for two times, namely by pre-scanning and fine scanning for the purpose of precise reading of the frame image. After the pre-scanning, a reading condition is determined according to density of the frame image and the like. In the fine scanning the frame image is read according to the determined reading condition. To protect the image reading from influence due to a scratch or dust stuck on the original, light from the light source is diffused and applied to the original. However, the influence of the scratch or dust of the original cannot be reduced completely even with the diffusion of the light applied to the original. Image reading at high precision is impossible.
There is a suggestion in JP-A 2001-016413, JP-A 2001-111795 and JP-A 2001-144908 in which the light source specialized for emitting infrared rays is disposed for detecting the scratch or dust from the original. The infrared rays after being reflected is detected to obtain infrared image data. According to this, the scratch or dust of the original is detected and checked, to correct image data obtained by the fine scanning.
In order to detect the scratch or dust by use of the infrared rays from a surface of the original, it is necessary to apply the infrared rays to the original in addition, and also to effect calculation for the scratch suppression according to the infrared image data. The processing of the scratch suppression takes considerable time, to lower efficiency in reading the frame image. A high-speed processing type of arithmetic operation processing device may be used. However, such a device is very expensive, to raise the manufacturing cost remarkably.